Method of producing transparent quartz.



A. VOELKER.

METHOD OF PRODUCING TRANSPARENT QUARTZ.

APPLICATION FILED FEB. 18, 1911.

Patented Aug. 18, 1914.

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AUGUST VOELKER, or BE EL, nimnnom GERMANY.

METHOD OF PRODUCING TRANSPARENT QUARTZ.

Specification of Letters'Patent. I

Patented Aug. 18, 1914.

Application filed February 18, 1911. Serial No. 609,466.

To all whom it may concern Be it known that 1, AUGUST subject of the German Emperor, and res1ding at 7 7" Siegburgerstrasse, Beuel, near Bonn-on-the-Rhine, Kingdom of Prussia, Germany, have invented certain new and useful Improvements in Methods of Producing Transparent Quartz, of which the following is a specification.

My invention consists of a method of producing tubular'bodies of transparent quartz. First a plastic opaque tubular body is formed in an electric furnace by fusing arenaceous quartz around a resistance heating core, then this plastic body is rolled on a layer of granular powder of pure rock crystal, and the so covered body 1s subsequently exposed to the action of a suitable source of heat so as to fuse the material and to render it transparent.

I will now proceed to describe 'my invention with reference to the'accompanying drawing, in which Figure 1 is a view of a plastic tubular body of opaque quartz on an electric resistance core, Fig. 2 illustrates the rolling of this body in a, layer of granular powder of rock crystal, and Fig. 3 illustrates the fus ing of the :so covered body by means of an electric arc.

Similar letters of reference refer to similar parts throughout the several views.

The difliculties experienced in making transparent quartz articles consist in first producing a body of approximately cylindrical or tubular shape and transparent material; when once this intermediate body of transparent material has been obtained it is a comparatively simple matter to transform it by inflating, pressing, dividing or other processes into the final form required.

With the aid of a heating process by electric resistance it is altogether not difficult to produce a cylindrical or tubular body of arcnaceous quartz by melting the latter around a thin carbon rod secured between electrodes. The body so obtained is however not transparent; it resembles ground glass and consists of a substance apparently still more opaque and rough than the latter, the non-transparency of which cannot be changed to any considerable extent, even by sending an electric current for some time through the heating core. Because if the electric current is sent for a longer time through the heating core than is just neces- VOELKER, a

sary for melting the quartz'or for converting the arenaceous quartz into a semi-liquid, tough mass, one may succeed, in obtaining a reduction of the viscosity of the molten product close around the heating core, which reduction may be valuable for producing clarification. and transparency, that is, driving out the air bubbles, but this will not be without a part of the molten product being evaporated, thus entailing a considerable loss. Furthermore, if the heating of the molten product is raised too highly or con tinued for too long a time, the' silicon will combine with the carbon of the core and a carbid of silicon (corundum) will be formed, which will of course stop the transparency of the molten quartz and pollute the latter. For making transparent quartz articles either pieces of rock crystal-are outwardly molten according to the customary methods and then combined in such state under a press to a cylindricalor tubular body,or the same intermediate body is built up of quartz-threads, which are wound in spirals and subsequently fused together.

The present invention now refers to a method for obtaining a cylindrical or tubular intermediate body such as required for making transparent quartz articles, and consists in a cylindrical or tubular body a, Fig. 1, being first prepared of arenaceous quartz in known manner by electric resistance heating, then after removing such body from the furnace again heating it so far that it assumes a semi-liquid consistency, whereupon it is rolled with the aid of a pair of tongs c (Fig. 2) gripping one end of the core 6 in granular powder d of pure rock crystal and finally exposed to the action of the electric arc (Fig. 3), an oXy-hydrogen flame or an electric muffle oven for such time, that it is fused to a transparent body and is now able to be further worked.

In Fig. 3 f denotes a sort of prismatic frame or casing open at the ends and made from refractory material, while 57 9 denotetwo opposite electrodes, which may be longitudinally guided in holes 1'- of the casing f and are connected by means of conductors i? h with some source of current. j denotes the arc and k a pulley driven by a belt Z for turning the core 7) with the body a.

The duration of the heating producing the last mentioned fusion depends obviously on the thickness and volume of the mass to be fused; the heating may be applied either locally, that is at single points, or over the fusing the product by externally heating the whole surface of the body under treatment. same. 10 I claim: in testimony whereof I hereto aflix my A process of making a transparent quartz signature in presence of two Witnesses. 5 body. from a tubular nucleus of non-trans- AUGUST VOELKER. f

- parent, arenaceous quartz in a state of In presence of fusion, consisting in rolling said nucleus in NICKOLAUS MEURER,

- a granular powder of rock crystal and in LoUIs VANDORY. 

